In medical diagnostics, in particular, numerous types of consumables are known, which are usually configured as disposable articles and have to be produced rapidly, reliably and cost-effectively. Thus, by way of example, the examination of blood samples or other samples of body fluids, for example interstitial fluid, in clinical diagnostics enables early and reliable identification of pathological states and also targeted and astute monitoring of body states.
Medical diagnostics generally presupposes that a sample of blood or interstitial fluid is obtained from the patient to be examined. For this purpose, the skin is usually perforated, for example at the finger pad or the ear lobe, with the aid of a sterile, pointed or sharp lancet in order thus to obtain a small amount of blood for analysis. Self-monitoring of blood sugar levels is a method of diabetes control that is nowadays applied worldwide. Blood sugar devices in the prior art generally have an analysis instrument which interacts with at least one analytical consumable, in particular a test element. In this case, the sample to be analysed is generally applied to a test field of the test element and reacts in the test field with one or more reagents, if appropriate, which are generally chosen in a manner specific to the analyte to be detected. This reaction can be detected, for example optically and/or electrochemically.
Analytical consumables in the form of test elements are just one exemplary embodiment of a multiplicity of consumables which are used in analytics, in particular medical analytics. Numerous further applications which use consumables are conceivable. In principle, the invention described below can be employed on all types of analytical consumables in accordance with the prior art.
When such analytical consumables are used, in particular in medical diagnostics, a number of technical challenges arise in practice, however, which have to be overcome by complex apparatus solutions. Thus, one difficulty consists in the fact that different types of analytical consumables which can be used in an analysis system can have differences among one another. Thus, by way of example, differences can arise with regard to the manufacturer and/or the production method, with regard to the detection reagents used, with regard to the analyte to be detected, with regard to the analysis method and/or analysis system to be used, with regard to the conditions under which the analysis is intended to be carried out, with regard to the parameters and/or the algorithms for the evaluation of measurements, with regard to the batch numbers, with regard to batch-specific special features, with regard to the manufacturing method, with regard to the number of analysis zones on a test element or the like. Information items about the above-mentioned differences and/or other types of differences should therefore be communicated to an analysis instrument which uses the analytical aid. In the case of analytical aids with lancets or other types of medical disposable articles, too, such article-specific information items can arise, in particular information items with regard to the manufacturer, the type of lancet, the lancet systems to be used or the like. Such items of information which are designed to enable at least one medical instrument to use the analytical consumable or components of said analytical consumable correctly are referred to hereinafter generally as function information items. Such function information items can comprise for example the abovementioned information items and/or further information items mentioned below. As an alternative or in addition, other information items can also be included. Function information items can comprise for example consumable-specific information items and/or aid-specific information items. In this case, the expression consumable-specific information items relates to information items concerning the analytical consumable as a whole, whereas aid-specific information items predominantly relate to individual analytical aids, for example individual test fields and/or lancets which are contained in the analytical consumable.
In many cases it is necessary, therefore, to correspondingly code an analytical consumable, that is to say provide it with a readable code, in order, as soon as this is necessary, to be able to provide these information items accordingly. One important exemplary application consists in automatic reading-in of functional information items, for example of consumable-specific information items, by an analysis instrument which is intended to use medical disposable articles, such as test strips, test tapes or lancets, for example. Since manual inputting and read-out of such function information items are generally unreasonable or even impracticable for the patient, various methods and systems in which function information items can be read in automatically are known from the prior art. Thus, by way of example, systems are known in which such function information items can be communicated by means of radio-frequency labels, data carriers that are to be inserted into a measuring instrument separately (for example so-called ROM keys) or similar code carriers. Such additional code carriers, as additional components, cause additional costs in production, however, which is generally undesirable. Moreover, user action is quite generally necessary, for example, insertion of the ROM key into a measuring instrument, which can integrate the possibility of incorrect operation.
Systems in which consumables themselves are coded are known from the prior art. DE 198 49 539 A1 describes a portable blood sugar measuring instrument for the self-monitoring of a diabetes patient. The measuring instrument uses a test strip for deter mining blood glucose, which is wound up as a tape with a plurality of measurement sections on a cassette. Said document proposes, inter alia, coding the production quality on the test tape in order to enable an automatic calibration of the blood sugar measuring instrument to the respective production batch of a tape cassette.
EP 0 299 517 A2 discloses a tape cassette for a biochemical analysis, which has a long test film with a detection reagent. Said document proposes, inter alia, providing at the beginning of the test tape a coding region on the test tape, which comprises at least one information item. Said coding region can be read out for example by means of the detector which is used for the optical measurement.
Known coding methods, such as the coding method described in EP 0 299 517 A2, for example, have numerous disadvantages and technical challenges in practice, however. Thus, such coding methods are comparatively complex, for example, since they necessitate a structured application of marking substances. This in turn makes technically stringent requirements of production, since this structuring has to be effected with high resolution and at the same time has to be able to be adapted flexibly to the information items to be written in. Furthermore, it should be taken into consideration that the coding process has to take place under conditions of high cleanliness since analytical aids contained in the analytical consumable ought not to be contaminated by coding materials.